What a Flame Sensor Is and Why It Matters

February 26, 2017

Receiving your annual furnace maintenance helps keep your heating system running up to 30 percent more efficient and helps extend the life of your furnace. But things could still go wrong, and when they do, you may feel like there is always something else.

This time it’s your motor, next time it’s your pressure switch. Now your find out the flame sensor has to be replaced.

What is a flame sensor, anyway?

A flame sensor is an important safety component on your gas heating system. During the ignition sequence, your gas furnace enters a process where either a spark or a hot surface igniter actually ignites the gas. When the gas is ignited, the flame sensor produces a current of electricity. The current is calculated in micro amps. If the furnace’s control board fails to read the right level of micro amps, the furnace will stop giving the system fuel to stop an explosion.

Over time, if the flame sensor is not adequately cleaned, oxidation or carbon buildup can interfere with the flame sensor’s ability to function properly, which can result in a malfunction of the furnace.

The way to diagnose if a soiled flame sensor is causing a furnace malfunction is to take a micro amp draw reading, which an expert heating technician can provide you. If a dirty flame sensor is the offender, the furnace expert will clean the sensor with steel wool. If dirt was the only factor, we will see a significantly higher amp reading. If the reading does not change, the technician will continue with the furnace repair diagnostic process.

If you aren’t confident your furnace is going to outlast these last few weeks of winter, give Broad Ripple Service Experts Heating & Air Conditioning a call and we’ll come out and perform a full furnace maintenance or a free in-home estimate on a new heating system.

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